The present invention relates generally to fluid lubricant dispensing equipment, and more particularly to a novel pistol-grip grease gun that can be operated in either pressure mode or volume mode.
A major advantage of pistol-grip grease guns is that they can be operated with only one hand. Heretofore, available pistol-grip grease guns only operated in one mode, usually the volume mode, but occasionally in the pressure mode. A grease gun user uses the volume mode when he/she wishes to get as much lubricant per stroke into a grease-fitting as possible. Often, a grease gun user will require the use of a pressure mode, such as when a grease-fitting is frozen, impeding the flow of lubricant, or when a bearing has such a high tolerance that getting lubricant into it requires more pressure
Prior art pistol-grip grease guns provide satisfactory volume mode performance. However, because of their inherent stroke and leverage limitations, large lubricant volume is provided at low pressure. When a pistol-grip grease gun user needed extra pressure in the past, he/she has been required to switch guns, resulting in inconvenience and reductions in productivity.
Grease guns that can operate both in pressure mode and volume mode, otherwise known as dual mode grease guns, are advantageous to the user. However, they are currently available only in lever-type grease guns. A major disadvantage of lever-type grease guns is that they require the user to use two hands, which is often not feasible. The only type of grease gun that allows the user to use only one hand is the pistol-grip grease gun.
Hence, there is a need in the art for a pistol-grip grease gun that can operate in both the volume mode and the pressure mode. The present invention satisfies this need.